Electrical apparatus and electronic devices such as computers and mobile phones may operate at different operating voltages of electrical source. Accordingly, electrical power is required to be stepped up or down to a suitable operating voltage for different electronic devices. It is also common that each of these apparatus or devices may comprises different operating modules which operates at different operating voltages, hence multiple power converters may be also included in these apparatus or devices.
In these electronic devices, power converters such as switching converters may be used to convert the electrical power to a required operating voltage. A switching converter includes switching network with a plurality of transistor switches, and operates at a high frequency during the power conversion process, which generate noise signal in a form of unwanted electrical and electromagnetic noise, and may affect the power source when transmitted back to the source from the conversion stage, hence the noise signal should be filtered by a filter in the input stage.